docs: def probePlayer(requested_player=''):
      """ Probes the multimedia players which are available on the host
      system."""
      ret_player = None
      if logger.isEnabledFor(logging.INFO):
          logger.info("Probing available multimedia players...")
      implementedPlayers = Player.__subclasses__()
      if logger.isEnabledFor(logging.INFO):
          logger.info("Implemented players: " +
                      ", ".join([player.PLAYER_CMD
                                for player in implementedPlayers]))
  
      if requested_player:
          req = requested_player.split(',')
          for r_player in req:
              if r_player == 'vlc':
                  r_player = 'cvlc'
              for player in implementedPlayers:
                  if player.PLAYER_CMD == r_player:
                      ret_player = check_player(player)
                      if ret_player is not None:
                          return ret_player
              if ret_player is None:
                  if logger.isEnabledFor(logging.INFO):
                      logger.info('Requested player "{}" not supported'.format(r_player))
      else:
          for player in implementedPlayers:
              ret_player = check_player(player)
              if ret_player is not None:
                  break
      return ret_player